GSK(GSK.US)Hepatitis B New Drug Proposed for Priority Review in China, Expected to Achieve Functional Cure for Hepatitis B

According to Tonghuashun Finance APP, on March 17, the official website of the Center for Drug Evaluation (CDE) of China’s National Medical Products Administration announced that GlaxoSmithKline (GSK.US) has applied for Bepirovirsen solution for injection to be included in priority review. This product is intended for limited-course treatment of chronic hepatitis B virus (HBV) infection and is suitable for the following populations: adults with chronic HBV infection who have previously been treated with nucleos(t)ide analogs, with HBsAg ≤3000 IU/mL, and no cirrhosis. Previously, this drug received breakthrough therapy designation in China. Its inclusion in priority review indicates that this is the world’s first antisense oligonucleotide therapy potentially capable of achieving functional cure of hepatitis B, bringing Chinese patients one step closer.

Public information shows that this is an investigational antisense oligonucleotide (ASO) therapy developed in collaboration between GSK and Ionis Pharmaceuticals. If approved, Bepirovirsen will become the world’s first antiviral therapy that can achieve functional cure of hepatitis B with only a 6-month limited course of treatment. GSK plans to formally submit for global regulatory approval in the first quarter of 2026, and the drug has already been filed for approval in Japan.

Bepirovirsen is an investigational ASO therapy with a triple mechanism of action, designed to identify and destroy the genetic components (RNA) of HBV, potentially allowing the immune system to regain control over the infection. Bepirovirsen can inhibit viral DNA replication in the body, reduce HBsAg levels in the blood, and activate the immune system, thereby increasing the chances of achieving a durable response. GSK obtained the rights to Bepirovirsen from Ionis Pharmaceuticals and is collaborating with them to advance the development of this drug.

In January 2026, GSK announced positive results from two pivotal Phase 3 clinical trials, B-Well 1 and B-Well 2, for the treatment of chronic hepatitis B. Both trials met their primary endpoints. Bepirovirsen demonstrated statistically and clinically meaningful rates of functional cure.

B-Well 1 and B-Well 2 are global, multicenter, randomized, double-blind, placebo-controlled trials designed to evaluate the efficacy, safety, pharmacokinetics, and durability of functional cure of Bepirovirsen in chronic hepatitis B patients receiving nucleos(t)ide analog therapy with baseline HBsAg ≤3000 IU/mL. The primary endpoint was the proportion of patients achieving functional cure among those with baseline HBsAg ≤3000 IU/mL. A key secondary endpoint was the proportion of patients with baseline HBsAg ≤1000 IU/mL achieving functional cure. Functional cure is defined as loss of HBsAg and undetectable HBV DNA at least 24 weeks after completing limited-course therapy.

Analysis showed that the B-Well trials met the primary endpoint, with Bepirovirsen demonstrating statistically and clinically significant rates of functional cure. Compared to standard therapy alone, Bepirovirsen combined with standard therapy significantly increased the rate of functional cure. All endpoints reached statistical significance, including in patients with baseline HBsAg ≤1000 IU/mL, where stronger effects were observed. The trials also showed that Bepirovirsen was well tolerated and safe, consistent with previous studies.